Hydrorefined lube oil and process of manufacture

ABSTRACT

A novel hydrorefined oil of improved stability under severe conditions of use has a viscosity in the range of 150-12,000 SUS at 100*F., contains 10-44 percent gel aromatics and less than 10 p.p.m. (preferably less than 5 p.p.m., more preferably less than 2 p.p.m. of basic nitrogen). Typically, such an oil can contain more than 10 p.p.m. of total nitrogen (e.g., 15-600 p.p.m.) depending on the viscosity of the oil. Preferably the hydrorefined oil is naphthenic or aromatic (by VGC classification). The basic nitrogen in such severely hydrorefined lube oils (typically 15-400 p.p.m.) can be reduced to less than 10 p.p.m. by a process comprising contacting the hydrorefined oil with an acidic adsorbent (such as an adsorbent comprising an acid-activated clay), preferably at 50*-150*F., or by contacting the hydrorefined oils with sufficient quantities of a mineral acid (e.g. 90-120 percent H2SO4) followed by a basic wash finished by adsorbent contact (as with a fuller&#39;&#39;s earth bleaching clay).

United States Patent 1 1 Mills et al.

Oct. 1, 1974 HYDROREFINED LUBE OIL AND PROCESS OF MANUFACTURE Inventors: Ivor W. Mills, Media; Glenn R.

Dimeler, West Chester, both of Pa.

Assignee: Sun Oil Company of Pennsylvania,

Philadelphia, Pa.

Filed: Feb. 24, 1972 Appl. No.: 228,832

Related US. Application Data Continuation-impart of Ser. Nos. 850,717, Aug. 18, 1969, abandoned, and Ser. No. 622,398, March 13, 1967, Pat. No. 3,462,358, and Ser. No. 652,026, July 10, 1967, Pat. No. 3,502,567, and Ser. No. 730,999, May 22, 1968, and Ser. No. 850,716, Aug. 18, 1969, abandoned, and Ser. No. 873,008, Oct. 31, 1969, abandoned, and Ser. No. 22,295, March 24, 1970, Pat. No. 3,681,233, and Ser. No. 165,006, July 22, 1971, and Ser. No. 165,141, July 22, 1971, Pat. No. 3,759,817, and Ser. No. 175,775, Aug. 27, 1971.

52 US. Cl 208/18, 208/98, 208/99,

' 208/264 Int. Cl Clg 41/00, ClOg 23/00 Field of Search 208/14, 18, 264, 143, 98,

[56] References Cited UNITED STATES PATENTS 8/1964 Anderson et a1. 208/14 7/1965 Mills et al. 208/14 12/1965 Anderson 208/28 2/1966 Watson et al 208/36 10/1968 Wynkoop et a1. 208/14 3,434,994 3/1969 Smit et a1 208/14 3,502,567 3/1970 Mills et a1. 208/14 FOREIGN PATENTS OR APPLICATIONS 743,525 9/1966 Canada 208 14 OTHER PUBLICATIONS Bruins, Plasticizer Technology, Vol. 1, Reinhold Pub. Co., N.Y., 1965, pages 79,80,85 and 86.

Von l-lippel, Dielectric Materials and Applications, Pub. John Wiley and Sons, London, (1961), pgs. 156 to 160.

Primary Examiner-l-lerbert Levine Attorney, Agent, or Firm-George L. Church; .1. Edward Hess; Barry A. Bisson [57] ABSTRACT A novel hydrorefined oil of improved stability under severe conditions of use has a viscosity in the range of ISO-12,000 SUS at 100F., contains l0-44 percent gel aromatics and less than 10 p.p.m. (preferably less than ppm, more preferably less than 2 p.p.m. of basic nitrogen). Typically, such an oil can contain more than p.p.m. of total nitrogen (e.g., -600 p.p.m.) depending on the viscosity of the oil. Preferably the hydrorefined oil is naphthenic or aromatic (by VGC classification). The basic nitrogen in such severely hydrorefined lube oils (typically l5400 p.p.m.) can be reduced to less than 10 p.p.m. by a process comprising contacting the hydrorefined oil with an acidic adsorbent (such as an adsorbent comprising an acid-activated clay), preferably at 150F., or by contacting the hydrorefined oils with sufficient quantities of a mineral acid (eg -120 percent H SO followed by a basic wash finished by adsorbent. contact (as with a fullers earth bleaching clay).

14 Claims, 3 Drawing Figures TOTAL NITROGEN AND BASIC NITROGEN VS ULTRAVIOLET ABSORFTIVITY FOR NAPTHENIC OILS 0F DIFFERING ISCOSITYlAT IOOF) ULTRAVIOLET ABSORPTIVITY AT 260 7)}!- PATENTEU 3.839.189

SHEET 1G 3 FIGURE I TOTAL NITROGEN AND BASIC NITROGEN VS ULTRAVIOLET ABSORPTIVITY FOR NAPTHENIC OILS OF DIFFERING VISCOSITY(AT IOO F) 6000 sus TOTAL NITROGEN AFTER HYDROREFINING 500- v 2500 sus BASIC NITROGEN AFTER HYDROREFINING E 300 3 2500 SUSA z g o 6000 sus 200 2 sus X o 2500 sus IIIEIIRII sus I A HYDROREFINING l 00 sus A I00 sus o 500 sus I50 sus x I50 sus so sus v 0 I 2 3 4 5 e '7 a 9 I0 I ULTRAVIOLET ABSORPTIVITY T 260 INVENTOR ATTORNEY PATENTED I SHEEI 2 0f 3 FIGURE 2 BASIC NITROGEN CONTENT VS ACID ACTIVATED CLAY DOSAGE Ema l zwwomtz 054d 2o ACID CLAY(EQUIVALENT TO 10.2 mg KOH per gram) LB./BBL.

INVEINTOR UV ABSORPTIVITY 280/289 mu.

PAIENIEBncI H974 smaar FIGURE 3 EFFECT OF HYDROGENATION TEMPERATURE ON UV ADSORPTIVITY.

A SUS PARAFF NIC \/ DISTILLATE LOO 60 SUS PARAEFINIC DISTILLATE TEMPERATURE INVENTOR.

ATTORNEY.

HYDROREFINED LUBE OIL AND PROCESS OF MANUFACTURE CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of all of the following earlier filed applications of the present inventors:

Filing Patent Issue ScrialNo. Date No. Date Title Filing Date Serial No.

Continued Filing Patent Issue Serial No. Date No. Date Title 850.717 8-18-69 now abandoned Hydrorefined Lube Oil and Process of Manufacture now abandoned Oil and Process of Manufacture of Blended 22.295 3-24-70 3,681,223 8-1-72 Hydrorefined Cable Oil and Process of Manufac- Y ture 165.006 7-22-71 Process for Producing Blended Petroleum Oil 165.141 7-22-71 3.759.817 9-81-73 Blend Comprising Hydrorefined Oil and Raw Distillate 175.775 8-27-71 Blended Hydrocarbon Oil and Process of Manufacture In addition to the previously noted patent applications the following earlier filed copending applications 20 are related to the disclosure of the present application:

Patent Issue No. Date Title 3.681.279 8-1-72 Process for Preparing An Aromatic Oil and Non-discoloring Rubber Composition Containing Said Oil-lVOR W. MILLS. GLENN R. DIMELER & MERRITT C. KIRK. JR. Rubber Containing Acid- Treated Oils and its Preparation-ABRAHAM SCHNEIDER & ARCHIBALD P. STUART High Modulus Composition Comprising Hydrocarbon Oil, Rubber and Carbon Black IVOR W. MILLS, GLENN R. DIMELER. MERRITT C. KIRK. JR. & JACKSON S. BOYER Catalytic Hydrofinishing of Petroleum Distillates in the Lubricating Oil Boiling Range IVOR W. MILLS. MERRITT C. KIRK. JR. & ALBERT T. OLENZAK lsomerization of Waxy Lube Streams and Waxes-1B STEINMETZ 84 DAVID S. BARMBY Process for Preparing Hign Viscosity Hydrorefined Cable Oil IVOR W. MILLS. GLENN R. DIMELER. WILLIAM A. ATKINSON & JAMES P. HOFFMAN Electrical Conduit Containing Hydrorefined Oil-IVOR W. MILLS. GLENN R. DIMELER & JOHN J. MELCHIORE Light Colored Highly Aromatic Oil and Process of Preparation- IVOR W. MILLS. GLENN R. DIMELER & MERRITT C. KIRK. JR.

Hyraulic Oil Composition Containing a Blended Base Stock JOHN Q. GRIFFITH. III. EDWARD S. WILLIAMS. WILLIAM H. REILAND. JR.. IVOR W. MILLS & GLENN R. DIMELER Textile Machinery Lubricant Composition-JAMES R. AMAROSO & JOHN Q. GRIFFITH. 111

now abandoned V Continued Issue Date Filing Date Patent Serial No. No

Title Catalytic Hydrofinishing of Lube Oil Product of Solvent Extraction of Petroleum Distillate-IVOR W. MILLS. MERRITT C. KIRK, JR. & ALBERT Tv OLENZAK Composition Comprising Blended Refrigeration Oil Composition IVOR W. MILLS & JOHN A. MELCHIORE i all the aboverefer redto tions is hereby incorporated herein by reference, particularly as to disclosure therein directed to hydrorefined oils in the lube viscosity range, to uses of such oils, and to the production of such oils.

RELEVANT PATENTS AND PUBLICATIONS In parent application Ser, No. 850,717, filed Aug. 18, 1969, which claimed a similar invention to that in the present application, (and which was allowed to become abandoned in view of the filing of the present application), the following references were cited by the Exammer:

Patent No. Issue Date Patentee Class/Sub U.S. Y 2,288,373 6/42 Smith et al 208/14 3,224,955 12/65 Anderson 208/18 3,328,293 6/67 Brenken 208/143 3,369,999 2/68 Donaldson et al 208/264 3,462,358 8/69 Mills et al 208/14 Canada 743,525 9/66 Cihula et al Publication: Von l-lippel Dielectric Materials and Applications pp. 156-l60, Wiley and Sons, London (1961 Other relevant patents, which the Examiner referred to at an interview, are the following:

US. Pat. No. 3,232,863 to Watson do. 3,425,932 to Surrena et all do. 3,459,656 to Rausch BACKGROUND OF THE INVENTION In copending application Ser. No. 622,398, now U.S. Pat. No. 3,462,358, a process is claimed for producing a an improved cable oil having an ASTM D-l934 aged dissipation factor (ADF) below 0.010 in the absence of added oxidation inhibitors, from a hydrogenated naphthenic oil having a viscosity in the range of 500-2,000 SUS at 100F., an ultraviolet absorbency (UVA) less than 8 at 260 millimicrons and having an ADF greater than 0.015, comprising contacting said oil ata temperature in the range of 100-400F., with an adsorbent comprising an acid-activated adsorbent clay in an amount per barrel of oil such that from 10-90 grams of KOH would be required to neutralize the acidity of the acid-activated adsorbent clay. Also claimed is a naphthenic electrical oil having a viscosity in the range of SOD-2,000 SUS at 100F., having an ADF less than 0.010 in the absence of added oxidation inhibitors, and which requires at least hours at PFVO test conditions to reach a 6 percent power factor. It was further disclosed tliat,inthe case of the high viscosity cable oils (4,0006,000 SUS at F.), a relatively inexpensive fullers earth bleaching clay was preferred as the adsorbent for such a hydrorefined oil and that the dosage of clay was not particularly critical insofar as the ADF of the resulting cable oil was concerned.

Also disclosed were hydrogenation conditions and catalysts which could be used to severely hydrorefine distillate oils in the lubricating oil viscosity range (35 and higher SUS at 100F. It'was further disclosed that such severe hydrogenation should be conducted so that the 260 UVA of the feed to the hydrogenation step be reduced at least 40 percent.

Further disclosed in said application, by example, was that the degree of nitrogen removal caused by the severe hydrorefining can vary according to the viscosity of the charge oil (an oil having a viscosity of 107 SUS and containing ppm. N produced an oil containing 47 ppm. N; whereas, an oil having a viscosity of 2,901 SUS and containing 467 ppm. of N produced, under the same hydrogenation conditions, an oil containing 313 ppm. of N).

BRIEF SUMMARY OF THE INVENTION It has been discovered that, in hydrorefined lubes having viscosities of 100 SUS or higher at 100F. (whether paraffins, naphthenic or aromatic), the total nitrogen content is not a reliable indicator of the stabilityof the oil under all conditions of use (as with refrigeration oils, textile oils, electrical oils, transmission fluids, etec.), but that the basic nitrogen content of the.

hydrogenated oil is an important indicator of how the oil (or blends containing the oil) will respond under severe conditions of use. In severely hydrorefined oils (as defined herein), the basic nitrogen content becomes a greater problem as the viscosity increases. It is a severe problem in oils of about 150 SUS and very severe in oils of 500 SUS or greater.

A novel hydrorefined oil of improved stability under severe conditions of use has a viscosity in the range of ISO-12,000 SUS at 100F., (typically, 500 SUS-6,000 SUS), contains l-44 percent gel aromatics and less than 10 p.p.m. (preferably less than p.p.m., more preferably less than 2 p.p.m.) of basic nitrogen. Typically, such an oil can contain more than p.p.m. of total nitrogen (e.g., -600 p.p.m.) depending on the viscosity of the oil and the severity of the hydrorefining. Preferably, the hydrorefined oil is naphthenic or aromatic by VGC classification; that is, it has a viscositygravity constant in the range of 0.820-0.94, or greater, (typically, 0.84-0.92).

The basic nitrogen in such severely hydrorefined lube oils (typically 15-400 p.p.m.) can be reduced to less than 10 p.p.m. by a process comprising contacting the hydrorefined oil with an acidic adsorbent (such as an adsorbent comprising an acid-activated clay), preferably at 50-150F., or by contacting the hydrorefined oil with sufficient quantities of a mineral acid (e.g., 90-120 percent H 80 followed by a basic wash to neutralize the oil and remove impurities (as by the procedures referred to in application Ser. No. 657,438 of Schneider and Stuart). More preferably, .the contacting is at a temperature in the range of 50-100F (e.g., 70F).

The oil which has been acid contacted and neutralized can be further finished (as may be desired for an electrical oil) by adsorbent contacting, as with a fullers earth bleaching clay (attapulgite), activated carbon, alumina, or a crystalline alumino-silicate zeolite (e.g., Linde 5A, or 13X molecular sieves), an acid-activated clay or combinations of two or more such adsorbents (e.g., see US Pat. No. 3,369,993). A preferred adsorbent combination is an admixture of attapulgite and acid-activated clay.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, FIG. 1 is a plot of the 260 UVA versus the nitrogen content (total or basic) of hydrorefined naphthenic oils of various viscosities. The hydrorefining of each charge oil was at 650F., 0.5 LHSV (of the fresh feed), 1,200 p.s.i.g. of 75 percent hydrogen (at the reactor inlet) with sulfided NiMo oxides on alumina as the catalyst. Also plotted is the basic nitrogen content of the charge stock (in the 100-2,500 SUS viscosity range) before hydrorefining.

FIG. 2 is a plot of the pounds of acid-activated clay (equivalent to 10.2 mg KOH per gram) required per barrel of hydrorefined oil to reduce the basic nitrogen to a given p.p.m. level in two of the severely hydrorefined naphthenic distillates from which the data plotted in FIG. 1 was obtained. The basic nitrogen is on a logarithmic scale, indicating that at lower concentrations it becomes increasingly more difficult to remove basic nitrogen with a single contacting step.

FURTHER DESCRIPTION OF THE INVENTION Petroleum fractions (e.g., distillates, extracts, raffinates, reformer bottoms, cycle oil fractions, etc.) in the lubricating oil viscosity range (35-12,000 SUS at 100F.) can be severely hydrorefined (e.g., at 600F., 1,200 p.s.i.g. of 80 percent hydrogen, 0.3 LHSV, presulfided Ni-Mo oxide catalyst) to produce a hydrogenated oil having a lighter ASTM color, a lower (by at least 40 percent, typically 40-90 percent) ultraviolet absorptivity at 260 millimicrons and containing appreciably less total nitrogen (and, if desired, lower gel aromatics) than was in the charge to the hydrorefining stage.

With some charges, such as paraffinic distillates, dewaxing and/or deasphalting can be advantageous prior to hydrorefining. Preferably, to insure longer catalyst life and to reduce hydrogen consumption, when the petroleum fraction is derived from a stock containing naphthenic acids, such acids should be removed (or substantially reduced) prior to hydrorefining as by the processes disclosed in the following US. Pat. Nos: 1,603,174; 2,770,580; 2,795,532; 2,966,456 and 3,080,312.

In the case of light lubes (e.g., having a viscosity in the range of 35-65 SUS at F.), such as the transformer oils, the total nitrogen remaining in the oil after a single stage of severe hydrogenation can frequently be less than 10 p.p.m. (typically, less than 5 p.p.m.). Hydrorefining can also be conducted (in a single stage or in multiple stages) so as to obtain a hydrorefined (or hydroaromatized) oil with such low nitrogen and an increased gel aromatic content (e.g., see Ser. No. 636,493).

Therefore, in light lubes and, particularly, in transformer oils, severe hydrogenation in a single stage is normally sufficient to reduce the basic nitrogen to less than 5 p.p.m. Generally, basic nitrogen is not a problem in such severely hydrorefined light lubes. Similarly, when the charge to a severe hydrorefining stage consists essentially of a paraffinic distillate in the lubricating oil boiling range, severe hydrogenation in a single stage is usually sufficient to effectively reduce both total and basic nitrogen to less than 10 p.p.m.

However, as is illustrated in FIG. 1 in the drawings attached hereto, when the charge stock is a naphthenic or aromatic distillate (including a raffinate or extract product from solvent extraction of a naphthenic distillate), having a viscosity greater than about 100 SUS, (typically -12,000 SUS) severe hydrogenation in a single stage, as to an ultraviolet absorptivity at 260 millimicrons (i.e., 260 UVA) in the range of 3 for a 150 SUS oil, cannot economically be used to reduce the basic nitrogen content below about 10 p.p.m., nor the total nitrogen content below about 20 p.p.m. As can be seen from FIG. 1, both the total and the basic nitrogen contents of such hydrorefined oils typically are greater as the viscosity of the oil increases. This is probably due to less efficient utilization of the hydrogen caused by the hindering effect of the larger oil molecules on hydrogen diffusion.

Also shown, in FIG. 2 is the dramatic degree to which such basic nitrogen can be removed from such a hydrorefined oil be means of an acidic adsorbent, particularly, acid-activated adsorbent clay.

For many uses (as in dark colored rubber vulcanizates or in electrical cables where the oil is not in contact with Kraft paper) such severely hydrorefined oils exhibit satisfactory performance even at total nitrogen levels in the range of 30-900 p.p.m. (about 50 percent of the total nitrogen being basic nitrogen). For certain end uses (such as in textile spinning oils, light colored oil-rubber vulcanizate, cables where the oil is in contact with Kraft paper and in refrigerator oils sub- I jected to high operating temperatures) a much more satisfactory performance. is obtained with a hydrorefined oil which has a viscosity in the range of l-l 2,000 SUS at 100F., contains -50 percent (typically 20-44 percent) of gel aromatics, and contains less than p.p.m. of basic nitrogen (preferably, less than 5 p.p.m. and more preferred less than 2 p.p.m.).

The phrase total nitrogen refers to the nitrogen content of an oil as determined by such methods as that of P. Gouverneur, Anal. Chim. Acta, 26 1962) 212 or, more preferred, the modified Gouverneur method described by Smith, A. J. et, al. in Anal. Chim. Acta, 40 (1968) 341-343.

The phrase basic nitrogen" refers to those nitrogen compounds present in crudes, petroleum distillates and residues which have a basic ionization constant, K greater than l A preferredanalytic method for determining the content of such basic nitrogen compounds in hydrorefmed oils in the lube oil viscosity range, involves dissolving a sample of the oil in an appropriate solvent and potentiometrically titrating the solution with perchloric acid in acetic acid. In the case of light-colored oils, the solvent can be glacial acetic acid and para-naphthol-benzein can be used as a colormetric indicator as an alternative to the potentiometric procedure. Dark samples and heavier oils are dissolved in chlorobenzene-acetic acid solvent and titrated potentiometrically (utilizing a pH meter or its equivalent and a glass-calomel electrode system).

For the potentiometric titration, the procedure is to place a gram sample of the oil in a 250 ml. tall-form titration beaker and add about 100 milliliters of a mixture of equal quantities of glacial acetic acid and chlorobenzene. The sample is then titrated potentiometrically, at room temperature, while being stirred continually by a magnetic stirrer, with 0.01 N perchloric acid in glacial acid to which has been added about 20 ml. of acetic anhydride for each liter of glacial acetic acid (in order to insure the removal of any water that might be present). The weight percent basic nitrogen is calculated as follows:

PPM Basic N (V,-V (N) (0.014) ,6/W

where:

V ml titrant for sample V ml titrant for blank N norrnality of perchloric acid W sample weight (grams) This potentriometric titration can be used to determine the basic nitrogen content of a hydrorefined oil in the range of 1 to at least 2,000 p.p.m. and, in the range of 1-l0 p.p.m. is at least accurate to within 1 p.p.m. when corrections are made for interferences by hydroxides, some oxides, carbonates, naphthenates, and similar bases (if these are present in the sample).

The phrases severe hydrorefining" or hydrogenation" refer to processes conducted in the presence of a hydrogenation catalyst at from about 500775F., with hydrogen of 50-100 percent purity, and from 800-3,000 p.s.i. of hydrogen at the reactor inlet (at total pressures from BOO-6,000 p.s.i.g.) at a fresh feed liquid hourly space velocity (LHSV) of from 0.1-8.0 (usually below 2.0), preferably conducted either in vapor phase or trickle phase. Such hydrogenation or severe hydrorefining is to be distinguished from hydrocracking in that the production ofoverhead (i.e., hy-

drocarbons boiling below 485F.) is less than 25 percent by volume per pass through the reactor (and, typically, less than 10 percent). Product recycle, for example, as in U.S. Pat. No. 2,900,433, can be used to increase severity. Recycle liquid hourly space velocity can vary from 0 to 20; however, we prefer to operate at total liquid throughputs that obtain at greater than 25 percent of flooding velocity and more preferably at from 40-98 percent of flooding velocity.

Preferably, the temperature is below that at which substantial cracking occurs, that is, no more than 20 weight percent (preferably less than 10 percent) of the feed stock is converted to material boiling below 300F. in a single pass through the reactor. Although the maximum hydrogenation temperature which will not produce substantial cracking is somewhat dependent upon the space velocity, the type of catalyst and the pressure, generally it is below 750F. but can be as high as 785F. To allow a margin of safety, we prefer to operate below 700F. (except when it is desired to obtain a hydrogenated oil containing more gel aromatics than are in the charge). At total pressures below about 2,000 p.s.i. we prefer a temperature below about 660F., since above that temperature the degradation of oil viscosity can become large.

Typical of such severe hydrorefining methods, when conducted within the aforementioned processing conditions, are those of U.S. Pat. Nos. 2,968,614; 3,993,855; 3,012,963; 3,114,701; 3,144,404; and 3,278,420; and those of the previously referred to copending applications, Ser. Nos. 622,398; 652,026; 636,493; 730,999 and 812,516. The terms severely hydrorefined oil or hydrogenated oil include the products, within the lubricating oil boiling range, of such severe hydrorefining or hydrogenation. One characteristic of a severely hydrorefined or hydrogenated oil is that the ratio of monocyclic aromatics to polycyclic aromatics is significantly greater than in hydrotreated oils or conventional distillate oils.

Where the desired hydrorefined oil is to be of the naphthenic class, a preferred charge to the hydrogenation reactor can be obtained by vacuum distillation of naphthenic or mildly aromatic crude oils (as in U.S. Pat. No. 3,184,396), especially those crude oils wherein the 1,5003,000 SUS (at F.) distillate fractions have viscosity-gravity constants from 0.84 to 0.92. Preferably, such a charge stock should be substantially free of naphthenic acids prior to the hydrorefining (thus, in some cases distillation in the presence of caustic is advantageous). Usually materials boiling below about 600F. (including residual H S, NHg, etc.) are removed from the hydrorefined oils, as by atmospheric distillation (and the viscosity can also be adjusted by choice of distillation end point) prior to clay contacting (if the oils are to be clay finished).

The viscosity of the base oil, or of the final hydrorefined oil, can be adjusted by the addition of other oils of higher or lower viscosity and whichare within the lube oil boiling range. For example, a preferred cable oil having a viscosity at 100 F. in the range of 500-2,000 SUS with hydrogenated oil having a viscosity from l,5003,000 SUS and then contacting the resulting blend of hydrogenated oils with sufficient acidic adsorbent or mineral acid to reduce the basic nitrogen content of the oil to below 10 p.p.m.

By napthenic distillate, we refer to a distillate fraction (or a mildly acid treated distillate fraction, or a solvent raftinate fraction or an acid-treated raffinate) usually from vacuum distillation, of a crude which is classified as naphthenic (including relatively naphthenic) by the viscosity-gravity constant (VGC) classification method. Preferably, such crudes are Grade A (waxfree), typically Gulf Coastal, and include, for example, Refugio, Mirando, and Black Bayou. The lower VGC oils can be obtained from mid-continental crudes; however, dewaxing may be necessary (as by extraction or isomerization) for end uses where the final oil is required to have a low pour point (e.g., less than 30F.) Such naphthenic fractions will have a VGC in the range of 0.820 to 0.899 and, typically, a viscosity in the range of ISO-12,000 SUS at 100F. (for example, 500-6,000). In some cases the crude (and distillate) can have a VGC as high as 094 (such crudes are characterized as mildly aromatic"), or higher (e.g., 0.96 Deep furfural extraction (e. g., aboutjQpercent yield) of a high VGC Grade A crude can be used to produce a wax-free, lower VGC fraction (e.g., 0.83 VGC) which can be used in low floc point (or pour point) blends with paraffinic oils (e.g., see Ser. No. 200,185). Paraffinic oils are those oils having a VGC of 0.819 or less and also having an ASTM viscosity index of 65 or more.

FURTHER DESCRIPTION OF THE DRAWINGS FIG. 1 herein illustrates the typical contents of total nitrogen and basic nitrogen for severely hydrorefined naphthenic oils in the viscosity range from 50 to over 6,000 SUS. The curves can be extended (either by mathematical means or by use gf a French curve), to obtain typical nitrogen contents of oils as high as 12,000 SUS at 100F.

In FIG. 1, two curves have been drawn to illustrate the relationship between the total and basic nitrogen content of severely hydrorefined oils of a number of viscosity ranges. The nitrogen content has been plotted against the 260 UVA, since the 260 UVA indicates the degree to which the oils have been hydrogenated. Also illustrated in a third curve is the basic nitrogen content of the charge oils before hydroretining.

For example, in FIG. 2, a 250 SUS naphthenic distillate (which was substantially free from naphthenic acid) was hydrorefined at 650F., 0.5 LHSV at 1,200 p.s.i.g. of 80 percent hydrogen (at the reactor inlet). The 2,500 SUS oil contained about 270 p.p.m. of basic nitrogen before the hydrorefining. The hydrorefined oil contained about 180 p.p.m. of nitrogen (and about 350 p.p.m. total nitrogen). The UVA of the 2,500 SUS distillate before hydrorefining was about 10.8 and, the hydrorefined oil had a 260 UVA of about 5.6, indicating a severe hydrogenation for such a relatively highly viscous distillate.

FIG. 2 of the drawings illustrates the degree to which the basic nitrogen in a hydrorefined oil can be reduced by contacting the oil with an acidclay. In the figure, the

10 the more highly viscous, hydrorefined oils, it becomes more economical to utilize a mineral acid, and to dilute the oils with a non-reactive, less viscous, lower boiling solvent (such as iso-octane or gas oil).

ILLUSTRATIVE EXAMPLES EXAMPLE I A 2,500 SUS naphthenic distillate (which was substantially free from naphthenic acid) was hydrorefined at 650F., 0.5 LHSV at 1,200 p.s.i.g. of percent hydrogen (at the reactor inlet). The 2,500 SUS oil contained about 270 p.p.m. of basic nitrogen before the hydrorefining. The hydrorefined oil contained about 180 p.p.m. of nitrogen (and about 350 p.p.m. total nitrogen). The UVA of the 2,500 SUS distillate before hydrorefining was about 10.8 and, the hydrorefined oil had a 260 UVA of about 5.6, indicating'a severe hydrogenation for such a relative highly viscous distillate. The appropriate values for the charge and hydrogenated oil produced from this charge are plotted in FIG. 1.

EXAMPLE II FIG. 2 of the drawings illustrates the degree to which the basic nitrogen in a hydrorefined oil can be reduced by contacting the oil with various amounts of an acidactivated clay. The upper curve in FIG. 2 shows the nitrogen levels which were obtained by such contact of the 2,500 SUS hydrorefined oil of Example 1. In the figure, the acid clay used had an acidity equivalent to 10.2 mg KOH per gram. In FIG. 2, the basic nitrogen is plotted on a logarithmic scale, indicating that as the lower levels of nitrogen content are approached, it becomes progressively more difficult to remove basic nitrogen with the acid clay adsorbent. The two curves in FIG. 2 illustrate that as the viscosity of the hydrorefined oil increases greater amounts of acid clay are necessary to reduce the basic nitrogen content to less than 10 p.p.m. (and or more preferably to less than 5 p.p.m.). With the more highly viscous, hydrorefined oils it becomes more economical to utilize a mineral acid, and to dilute the oil with a non-reactive, less viscous, lower boiling solvent (such as iso-octane or gas oil). Such contacting with a mineral acid can be by the processes shown in the previously referred toapplications Ser. No. 622,398 (now U.S. Pat. No. 3,462,358 or Ser. No. 652,026 (now U.S. Pat. No. 3,502,567). Other preferred processes for removing basic nitrogen from such oils are those shown in the application of Schneider and Stuart, Ser. No. 657,438. Cables containing Kraft paper and the oils containing less than 5 p.p.m. of basic nitrogen show good performance under service conditions, (see Ser. No. 850,779, now U.S. Pat. No. 3,586,752).

EXAMPLE III A residuum was obtained from the distillation of a naphthenic crude (VGC of 0.89) by the caustic distillation process described in U.S. Pat. No. 3,184,396. This residuum was distilled under a lower pressure than that used in the first distillation and a 35 volume percent overhead fraction (viscosity 13,000 SUS at F. and 200 SUS at 210F.) was recovered. This overhead will be referred to hereinafter as heavy distillate from heavy residuum or by the abbreviation HDFI-IR." The HDFHR was hydrorefined, in the presence ofa sulfided Ni-Mo oxide catalyst. at a temperature of about 605F., 1,140 p.s.i.g. total pressure (about 75 percent H at reactor inlet), at a 7 to 1 volume ratio of recycle to charge and with a reactor gas bleed of 18,000 scfh. The hydrogenated product (95volume percent yield) distillate, a hydrogenation temperature in the range of 565640F. can be used to produce a hydrogenated oil having a 280-289 UVA less than 1.0. At hydrogen pressures in the range of 800-2,000 p.s.i., a temperahad a viscosity at lF. of 8050 SUS and 170 SUS at ture ofabout 575F. (or a range of 565585F) can be 210F. this hydrogenated oil had an initial ASTM color used to provide an optimum hydrogenation (as indiof 2.0 and remained stable in color if stored at temperacated by a low 280-289 UVA) for paraffinic distillates tures below 130F. when contacted with lb/bbl. of having viscosities in the range of 50-600 SUS at 100F. H 80 washed and neutralized-and finished with 10 Such hydrogenated oils can be advantageously finished lb./bbl. of attapulgite. The final oil had an initial power 10 with acidactivated or fullers earth bleaching clays or factor (100C.) of 0.0006 and an aged (with Cu) with mixtures of such clays (5-50 lbs/bbl). Table ll 100C. power factor of 0.012. herein reports on further properties of such technical Table 1 herein reports the additional improvement in white oils. electrical properties which can be obtained when the TABLE 1 HDFHR is treated with an acid such as H 80 washed and neutralized prior to the, hydrogenation s00 sus (at 1000 Cable Oils Made From Heavy step. Also shown is the additional improvement which Dlslllme {mm fi E X Dim mm Fmm E can be Obtalned y final Contactmg wlth acld' Step Further Treatment Nitrogen lnitial At Aged,4 days activated ofHDFHR ppm 100C. Cu, 115C. A preferred class ofhydrorefined oil of the present 1st H250 1nvent1or1 1s characterized by having an ASTM-VI of 2nd Hydrogenation 1 0.0361 less than 65 (typically less than 50) and containing at 3rd least 20 wt. percent aromatics (typically -45 per- 1st Mb 142,50l cent). Generally, the Engler viscosity at.20C. will be 23 "tee than loouypically, Over Techflical grade 25 2nd Tlydrogenati n 1 0.0002 0.0160 white oils, useful as agrucultural spray oils, or for 3rd 10 lh/hbl acidblending with the novel oils discussed above, and havfiff' fifig flf ing viscosities in the range of -600 SUS at 100F. can 2nd Hyrogenatidn 8 1:1 40 lh/bhl H be made fr.om hydrogenated paraffimc & when the 2:10 Hydrogenation 1 0.0001 0.0092 hydrogenation is effected under the condltlons shown 30 3rd l0 lb/bhl acidin the accompanying FIG. 3 and Table ll. Such technimilled C y Commercial Polycal white o1ls can have 1mproved ox1dat1on stab1l1ty 1f butane they are blended with from 1-10 percent of unhy- (2500 505 at 7 d n w stsffisi ei t ets nd 0936 919959999 W TABLE II Ultraviolet Absorptivity Data for Hydrogenated Paraffinic Distillates Hydrogenation Conditions (1000 gig of l00% H8) FDA Absorptivities. mu. UV Absorptivities, mu.

Run TempF. LHSV 280/289 290/299 300/329 330/350 260 335 A"' (Charge) 10.73 8.85 7.45 3.30 0.93 0.08 0.05

Spec. FDA Tech. White 011 4.0 3.3 2.3 0.8

(a) 500 SUS paraffinic distillate charge hydrogenated at indicated conditions (Runs B-G). (b) 60 S US at F. paraffinic distillate charge hydrogenated at indicated conditions (Runs H and l).

(0) Sample H (650F.. 0.5 LHSV) rerun at 550F. 0.5 LHSV (2 stage process).

can be added to the hydrorefined naphthenic and aromatic oils described herein).

FIG. 3 illustrates the ultraviolet absorptivity in the 280-289 millimicron region for paraffinic distillates of varying viscosities (60 SUS and 500 SUS, respectively). The curves show that within a very narrow temperature range the UV absorptivity in the 280-289 millimicron region (280-289 UVA) can be minimized. At a temperature between 550-600F., a 500 SUS distillate can be hydrogenated, at 800 p.s.i. or more of hydrogen partial pressure, to produce a technical white oil having a 280-289 UVA less than 2.0. For a 60 SUS paraffinic The invention claimed is:

l. A severely hydrorefined oil having improved stability under severe conditions of use and having a viscosity in the range of 2050l2,000 SUS at 100F, said severely hydrorefined oil containing l0-44 wt percent gel aromatics and less than 10 ppm of basic nitrogen, and wherein said severely hydrorefined oil has a viscosity gravity constant in the range of at least 0.84 to 0.92.

2. A hydrorefmed oil according to claim 1 and containing more than 10 ppm. of total nitrogen.

3. A hydrorefined oil according to claim 1 and containing from 15-600 ppm. of total nitrogen.

4. A hydrorefined oil according to claim 3 and containing less than 2 p.p.m. of basic nitrogen.

5. A hydrorefined oil according to claim 1 wherein said hydrorefined oil has a viscosity in the range of 8,100-12,000 SUS at 100F.

6. A hydrorefined oil according to claim 1 wherein said hydrorefined oil has a viscosity in the range of 2050-2950 SUS at 100F.

7. Process for preparing a hydrorefined oil containing less than ppm of basic nitrogen, said process comprising obtaining a severely hydroret'med oil having a viscosity-gravity constant of at least 0.84, a viscosity at 100F in the range of 2050l2,000 SUS and containing more than 10 ppm of basic nitrogen, and contacting said oil with an acidic adsorbent or a mineral acid and recovering as a product of said contact a severely hydrorefined oil containing less than 10 ppm of basic nitrogen.

8. Process according to claim 7 whereinthe basic nitrogen content of said severely hydrorefined oil is determined prior to said contacting.

9. Process according to claim 7 and wherein said contacting is with an adsorbent comprising an acidactivated adsorbent clay.

10. Process according to claim 8 wherein said contacting is at a temperature in the range of 50-l50F.

11. Process according to claim 9 and wherein said adsorbent comprises acid-activated adsorbent clay and a naturally occurring fullers earth bleaching clay.

12. Process according to claim 10 and wherein said naturally occurring fullers earth bleaching clay is attapulgite.

13. Process according to claim 7 wherein said mineral acid is -120 percent H 50 14. A process according to claim 7 wherein the total nitrogen in said hydrorefined oil prior to said contacting is greater than 50 p.p.m. 

1. A SEVERELY HYDROFINED OIL HAVING IMPROVED STABILITY UNDER SEVERE CONDITIONS OF USE AND HAVING A VISCOSITY IN THE RANGE OF 2050-12,000 SUS AT 100*F, SAID SEVERELY HYDROREFINED OIL CONTAINING 10-44 WT PERCENT GEL AROMATICS AND LESS THAN 10 PPM OF BASIC NITROGEN, AND WHEREIN SAID SEVERELY HYDROREFINED OIL HAS A VISCOSITY GRAVTIY CONSTANT IN THE RANGE OF AT LEAST 0.84 TO 0.92.
 2. A hydrorefined oil according to claim 1 and containing more than 10 p.p.m. of total nitrogen.
 3. A hydrorefined oil according to claim 1 and containing from 15-600 p.p.m. of total nitrogen.
 4. A hydrorefined oil according to claim 3 and containing less than 2 p.p.m. of basic nitrogen.
 5. A hydrorefined oil according to claim 1 wherein said hydrorefined oil has a viscosity in the range of 8,100-12,000 SUS at 100*F.
 6. A hydrorefined oil according to claim 1 wherein said hydrorefined oil has a viscosity in the range of 2050-2950 SUS at 100*F.
 7. Process for preparing a hydrorefined oil containing less than 10 ppm of basic nitrogen, said process comprising obtaining a severely hydrorefined oil having a viscosity-gravity constant of at least 0.84, a viscosity at 100*F in the range of 2050-12,000 SUS and containing more than 10 ppm of basic nitrogen, and contacting said oil with an acidic adsorbent or a mineral acid and recovering as a product of said contact a severely hydrorefined oil containing less than 10 ppm of basic nitrogen.
 8. Process according to claim 7 wherein the basic nitrogen content of said severely hydrorefined oil is determined prior to said contacting.
 9. Process according to claim 7 and wherein said contacting is with an adsorbent comprising an acidactivated adsorbent clay.
 10. Process according to claim 8 wherein said contacting is at a temperature in the range of 50*-150*F.
 11. Process according to claim 9 and wherein said adsorbent comprises acid-activated adsorbent clay and a naturally occurring fuller''s earth bleaching clay.
 12. Process according to claim 10 and wherein said naturally occurring fuller''s earth bleaching clay is attapulgite.
 13. Process according to claim 7 wherein said mineral acid is 90-120 percent H2SO4.
 14. A process according to claim 7 wherein the total nitrogen in said hydrorefined oil prior to said contacting is greater than 50 p.p.m. 